On Oct. 16, 2009, the U.S. Food and Drug Administration (FDA) approved new indication for gardasil to prevent genital warts in men and boys. The vaccine works by blocking the two strains of the human papilloma virus, or HPV, which causes irregular growths and rare types of cancer in male genitals.

On Oct. 21, 2009, the Advisory Committee on Immunization Practices (ACIP) provided guidance that HPV4 may be given to males aged 9 through 26 years to reduce their likelihood of acquiring genital warts; ACIP did not recommend HPV4 for routine use among males.